All true. Just for kicks, I ran his numbers first through one of my aviation calculators, and then here:

http://wahiduddin.net/calc/calc_hp.htm
The numbers agreed in both cases: a Density Altitude of ~7.7K, and Relative Density of 79.3%. In other words, a N/A car will make 79.3% of standard day, sea-level power. Additionally, the Tuner's Calculator suggests an SAE correction of ~1.237, so Mac really didn't pump up the number on the dyno. Again, that's an N/A correction. (note, you have to plug numbers for DP and/or RH - they don't matter anywhere near as much as PA and Temp.) So, assuming Phatron's number of 50%, that should give a "true" correction factor of ~1.119. That gives the OP a wheel power of 437/471. No matter how you slice it, that's a buttload of power at a DA of 7.7K' elevation. (for those of you who do the calcs, you'll notice that the corrected air pressure that day was pretty high; ~ 30.39)

Phatron, does the NHRA say that the "half correction" is a

__constant__? Second, looking at the 50% correction factor power numbers, in your experience how does those line up with E85, with his injectors at 91% DC's at 7K rpm and 24 psi?